This invention relates to a device for use in an environment where flammable gases may be present, and, more particularly to such a device including an exterior housing, with an electrical component and battery inside the housing.
Some devices containing an electrical component have been made of polycarbonate, and polycarbonate is known to have adequate tensile strength and no ability to hold an electrical charge, i.e., it cannot be rubbed with a cloth to create a charge. See U.S. Pat. No. 6,409,942.
Polycarbonate has also been used as a lens for an explosion proof light source is old. See U.S. Pat. Nos. 4,112,485, 4,264,946, 5,534,664, 6,371,625, 6,409,942, and 7,086,283.
In U.S. Pat. No. 4,112,485, it was noted that electric lamps are known in which a light source is placed into a transparent casing and tightly enclosed therein (see German Patent DGM No. 1833690). In other versions, one or several light sources are directly and tightly surrounded with transparent cast polyester or similar material and designated as “explosion-proof” (see British Patent No. 1166442 and U.S. Pat. No. 3,310,670).
None of this prior art addresses how to make a remote control device that can be used in an environment where flammable gases may be present.
Viebrantz et al. U.S. Pat. No. 4,768,230 is directed to a sealed housing for a hand-held remote control transmitter, and Toth et al. U.S. Pat. No. 3,974,933 is directed to an explosion proof and watertight enclosure.